1. Field of the Invention
The present invention relates to a process for conducting textile printing for dyeing a cloth black by an ink-jet system, a print obtained by such a process, and a processed article.
2. Related Background Art
At present, textile printing is principally conducted by screen printing or roller printing. Both methods are however undesirable to produce a variety of items in a small quantity and difficult to quickly cope with the fashion of the day. Therefore, there has recently been a demand for establishment of an electronic printing system making no use of any plates. In compliance with this demand, a great number of printing processes, to which an ink-jet system is applied, have been proposed. Various fields expect much of such printing processes.
Technical requirements for the printing processes, to which an ink-jet system is applied, include:
(1) to apply coloring matter to a cloth at a sufficient concentration for coloring;
(2) to give a high coloring yield of coloring matter to a cloth and an easy waste water treatment after a washing step;
(3) to alleviate irregular bleeding due to color mixing between inks of different colors on a cloth;
(4) to provide prints with wide color reproductivity; and
(5) to produce prints with stable coloring ability.
Among these, the item (1) has been very difficult to solve because the absolute quantity of dyes able to be applied to a cloth in the printing processes, to which an ink-jet system is applied, is less than that in the conventional printing processes. In order to meet this requirement, there have heretofore been mainly made such countermeasures that a concentration of a dye in an ink is enhanced, and a cloth is subjected to a pretreatment. With respect to images of high saturation, coloring comparable to the conventional printing processes has been achieved by these efforts.
However, a problem has yet remained in the expression of xe2x80x9ccomplete black colorxe2x80x9d in the ink-jet textile processes.
Such a problem has been generally managed by experienced color matching. In the ink-jet textile printing also, for example, Japanese Patent Application Laid-Open No. 8-127730 discloses that the combination of a specified black reactive dye (C.I. Reactive Black 5) and a specified yellow, orange or red reactive dye is preferred from the viewpoints of ink properties and the tint of black.
The present inventors have revealed that all the combinations disclosed in this publication are unified to only dyes having a vinylsulfone group as a reactive group to cloths. The unification of the kinds of reactive groups is certainly meaningful because no time lag is caused in the reactions with a cloth, and so reaction conditions can be unified. However, when coloring materials of black and orange are contained in the same ink as described above, there is involved a problem that such an ink cannot be used for a variety of cloths because the added proportions of these coloring materials cannot be changed. More specifically, since the degree of scattering of light on the surface of a cloth and the feeling thereof are different with cloths, the added proportions of the coloring materials of black and orange for obtaining far excellent xe2x80x9ccomplete black colorxe2x80x9d vary with the cloths. For example, the proportions of the coloring materials of black and orange for cellulose must be naturally changed from those for silk. Further, since a water content in a cloth varies with the season and the like, and so a coloring yield to the cloth, and the like naturally vary, the contents of the coloring materials must be changed. However, it is not preferable from the viewpoints of cost and practical use to provide inks according to the type and condition of a cloth.
Therefore, the present inventors have investigated as to the color matching of black in textile prints by applying a black ink containing C.I. Reactive Black 5 and an orange ink containing a reactive dye having a monochlorotriazinyl group as a reactive group so as to partialy overlap each other.
Since reactive dyes used in inks are selected in consideration of not only the color-fixing property to a cloth, but also durability after color fixing, the types of reactive groups of reactive dyes contained in a black ink are not always unified. However, It is not generally preferable to use reactive dyes respectively having reactive groups different from each other in textile printing, and particularly, it has not yet been known to use reactive dyes respectively having reactive groups different from each other in color matching of black for textile prints. Under such circumstances, the present inventors have carried out a further investigation. As a result, it has been found that two types of reactive dyes, which respectively have reactive groups different from each other, i.e., exhibit different reactivities to a cloth, can improve the tint of black in textile prints, thus leading to completion of the present invention.
It is therefore an object of the present invention to solve such problems involved in the conventional ink-jet printing processes as described above when textile printing is conducted on a cloth composed mainly of fiber dyeable with reactive dyes by an ink-jet system, and particularly to provide an ink-jet printing process which can stably provide a high-density print of an achromatic black color even when the type and condition of a cloth, or conditions for a dyeing treatment by heating somewhat vary, together with a textile print obtained by such a process and a processed article.
The above object can be achieved by the present invention described below.
According to an embodiment of the present invention, there is thus provided a textile printing process for dyeing a cloth black, the cloth comprising fibers dyeable with reactive dyes, the process comprising at least three steps of:
(a) applying a black ink containing a black reactive dye and an orange ink containing an orange reactive dye to the cloth so as to at least partialy overlap each other by an ink-jet system;
(b) heating or steaming the cloth, to which the inks have been applied in the step (a); and
(c) washing the cloth resulted from the step (b), wherein the black and orange reactive dyes have reactive groups different from each other.
According to an embodiment of the present invention, there is also provided a print obtained in accordance with the textile printing process described above.
According to another embodiment of the present invention, there is further provided a print dyed with black and orange dyes in a state at least overlapped, wherein the balck dye comprises at least one selected from the group consisting of C.I. Reactive Black 5, 14 and 31, and the orange dye comprises at least one dye selected from the group consisting of C.I. Reactive Orange 5, 12, 13 and 35.
According to an embodiment of the present invention, there is still further provided a processed article obtained by processing the print described above.
According to another embodiment of the present invention, there is yet still further provided a processed article obtained by cutting out the print described above into pieces of prescribed sizes and processing at least one of the pieces.
The present inventors have carried out an investigation for satisfying the above-described requirements for performance as to the ink-jet printing processes at the same time. As a result, it has been found that the expression of an achromatic black color can be stably achieved by separately applying a black and orange inks with the proportion of the black and orange dyes contained therein varied even when conditions for a fixing treatment are changed according to the types and conditions of cloths, so that the range of selection as to dyes to be combined can be widened.
As a reactive dye capable of achieving a deep black color, is preferred a dye having an azo group as a chromophore. In the case of the reactive dye, however, a limitation is imposed on the molecular structure of the dye because an unreacted dye must be washed out. Such a black reactive dye may often develop a color tone of navy blue by itself. When an orange reactive dye is shot herein, a print of an achromatic black color can be provided.
When the black reactive dye and the orange reactive dye are shot in a proportion of 1:2 to 8:1 in terms of a weight ratio of the black reactive dye to the orange reactive dye, a high-density print of an achromatic black color can be provided.
A limitation is imposed on the greatest amount of a dye contained in an ink for satisfying the viscosity and resistance to clogging in an ink for ink-jet printing. According to the process of the present invention, however, a black dye can be contained in an ink to the greatest amount over which the limitation is imposed.